Neural Activation during Covert Processing of Positive Emotional Facial Expressions

Abstract

Lesion studies indicate distinct neural systems for recognition of facial identity and emotion. Split-brain experiments also suggest that emotional evaluation of a stimulus can occur without conscious identification. The present study tested a hypothesis of a differential neural response, independent of explicit conscious mediation, to emotional compared to nonemotional faces. The experimental paradigm involved holding in mind an image of a face across a 45-s delay while regional cerebral blood flow was measured using positron emission tomography. Prior to the delay, a single face was presented with an explicit instruction to match it to one of two faces, photographed at different angles from the target face, presented at the end of the delay. Repeated blood flow measures were obtained while subjects held happy or neutral faces in mind or during a neutral control fixation condition without initial face presentation. The representation of emotional faces over a delay period, compared to either the nonemotional or the fixation condition, was associated with significant activation in the left ventral prefrontal cortex, the left anterior cingulate cortex, and the right fusiform gyrus. The findings support our hypothesis of a differential neural response to facial emotion, independent of conscious mediation, in regions implicated in the processing of faces and of emotions. r 1996 Academic Press, Inc.

Common regions of dorsal anterior cingulate and prefrontal–parietal cortices provide attentional control of distracters varying in emotionality and visibility

“…There are also data suggesting that they may also be mutually excitatory, or at least that the amygdala may excite rACC (Budhani et al, 2007;Nakic et al, 2006;Pezawas et al, 2005). Specifically, rACC is found active in affective stimuli processing (Breiter et al 1996;Dolan et al 1996;Elliott et al 2000;George et al 1993). It is therefore possible that some of the results that were suggested to indicate control over the amygdala's response actually represented excitatory activation from the amygdala.…”

Extended Amygdala and Emotional Salience: A PET Activation Study of Positive and Negative Affect

“…A fourth condition (blank condition, BL) consisted of a white fixation cross on a gray background (five different shades). Since processing of faces recruits specific brain regions (Dolan et al, 1996;Haxby et al, 1996), we matched the sets (POS, AV, NA) with respect to faces and human figures. In addition, to avoid possible differential effects of color composition (ie more red in aversive images), all images were transformed into black and white, and luminance was balanced across the four sets with Photoshop 4.0 (Adobe Systems).…”

Limbic Activation and Psychophysiologic Responses to Aversive Visual Stimuli Interaction with Cognitive Task

“…Neutral pictures were selected which did not elicit strong emotions, positive or negative, such as people at rest, faces with neutral expressions, and benign scenes. Since processing of faces recruits specific brain regions (Dolan et al 1996;Haxby et al 1996), we matched the neutral and negative pictures with respect to the number of slides portraying faces and human figures.…”

“…Neutral pictures were selected which did not elicit strong emotions, positive or negative, such as people at rest, faces with neutral expressions, and benign scenes. Since processing of faces recruits specific brain regions (Dolan et al 1996;Haxby et al 1996), we matched the neutral and negative pictures with respect to the number of slides portraying faces and human figures.The tasks consisted either of the subjects rating the pictures for aversive content ( rating ) or determining whether the pictures had been previously presented ( recognition ). In the rating phase, subjects received instructions to rate each picture verbally on a 5-point scale (5 ϭ extremely disgusting and 1 ϭ not at all disgusting), indicating the degree to which they found the image disgusting.…”